c2pa-rs

commit 1804adb63945639f509ef0bccf9c5bd528395191
parent d9e052b594b1fa87bf639a1b167b8c26dd532513
Author: mauricefisher64 <92736594+mauricefisher64@users.noreply.github.com>
Date:   Thu, 13 Jul 2023 12:12:33 -0400

Fix iloc extent_offsets when offset_size is 0 (#277)


Diffstat:
M
sdk/src/asset_handlers/bmff_io.rs
 | 
51
++++++++++++++++++++++++++++++++++++++++++++++++++-

1 file changed, 50 insertions(+), 1 deletion(-)
diff --git a/sdk/src/asset_handlers/bmff_io.rs b/sdk/src/asset_handlers/bmff_io.rs
@@ -826,7 +826,8 @@ fn adjust_known_offsets<W: Write + CAIRead>(
                         None
                     };
 
-                    let _extent_offset = match offset_size {
+                    let extent_offset_file_pos = output.stream_position()?;
+                    let extent_offset = match offset_size {
                         0 => 0_u64,
                         4 => output.read_u32::<BigEndian>()? as u64,
                         8 => output.read_u64::<BigEndian>()?,
@@ -837,6 +838,54 @@ fn adjust_known_offsets<W: Write + CAIRead>(
                         }
                     };
 
+                    // no base offset so just adjust the raw extent_offset value
+                    if constuction_method == 0 && base_offset == 0 && extent_offset != 0 {
+                        output.seek(SeekFrom::Start(extent_offset_file_pos))?;
+                        match offset_size {
+                            4 => {
+                                let new_offset = if adjust < 0 {
+                                    extent_offset as u32
+                                        - u32::try_from(adjust.abs()).map_err(|_| {
+                                            Error::InvalidAsset(
+                                                "Bad BMFF offset adjustment".to_string(),
+                                            )
+                                        })?
+                                } else {
+                                    extent_offset as u32
+                                        + u32::try_from(adjust).map_err(|_| {
+                                            Error::InvalidAsset(
+                                                "Bad BMFF offset adjustment".to_string(),
+                                            )
+                                        })?
+                                };
+                                output.write_u32::<BigEndian>(new_offset)?;
+                            }
+                            8 => {
+                                let new_offset = if adjust < 0 {
+                                    extent_offset
+                                        - u64::try_from(adjust.abs()).map_err(|_| {
+                                            Error::InvalidAsset(
+                                                "Bad BMFF offset adjustment".to_string(),
+                                            )
+                                        })?
+                                } else {
+                                    extent_offset
+                                        + u64::try_from(adjust).map_err(|_| {
+                                            Error::InvalidAsset(
+                                                "Bad BMFF offset adjustment".to_string(),
+                                            )
+                                        })?
+                                };
+                                output.write_u64::<BigEndian>(new_offset)?;
+                            }
+                            _ => {
+                                return Err(Error::InvalidAsset(
+                                    "Bad BMFF: unknown extent_offset format".to_string(),
+                                ))
+                            }
+                        }
+                    }
+
                     let _extent_length = match length_size {
                         0 => 0_u64,
                         4 => output.read_u32::<BigEndian>()? as u64,